Method of producing inorganic sorbents for extracting lithium from lithium-containing natural and technological brines

Abstract

Disclosed is a method of producing inorganic sorbents for extracting lithium from lithium-containing natural and technological brines. The method is carried by contacting a soluble niobate (V) with an acid in the presence of at least one zirconium (IV) salt to obtain a precipitate of a mixed hydrated niobium and zirconium oxide. Subsequent steps include granulating the precipitate by freezing, converting the product of granulation into a Li-form, calcining the Li-form, and converting the obtained granulated mixed lithium, niobium, and zirconium oxide into an ion-exchanger in an H-form. In the obtained H-form the inorganic sorbent is ready for use in lithium extraction processes.

The invention claimed is: 
     
       1. A method of producing inorganic sorbents for extracting lithium from lithium-containing natural and technological brines, the method comprising the steps of:
 contacting a soluble niobate (V) with an acid in the presence of at least one zirconium (IV) salt to obtain a precipitate of a mixed hydrated niobium and zirconium oxide, which is a non-stoichiometric compound; 
 granulating the obtained precipitate of a mixed hydrated niobium and zirconium oxide by freezing with subsequent defreezing to obtain a granulated mixed hydrated niobium and zirconium oxide; 
 converting the obtained granulated mixed hydrated niobium and zirconium oxide into a Li-form of the granulated mixed hydrated niobium and zirconium oxide by treating the granulated mixed hydrated niobium and zirconium oxide with a lithium-containing compound selected from the group consisting of a solution of lithium hydroxide LiOH and a solution of Li 2 CO 3 ; 
 calcining the Li-form of the granulated mixed hydrated niobium and zirconium oxide to obtain a granulated mixed lithium, niobium, and zirconium oxide, which comprises a tripled mixed oxide, which is a Li-form of an inorganic ion-exchanger; and 
 converting the obtained granulated mixed lithium, niobium, and zirconium oxide to an ion-exchanger in an H-form by treating the granulated mixed lithium, niobium, and zirconium oxide with an acid solution. 
 
     
     
       2. The method of  claim 1 , wherein the step of contacting a soluble niobate (V) with an acid in the presence of at least one zirconium (IV) salt is carried out with an ion ratio of niobium (V) to zirconium (IV) in the soluble niobate and at least one zirconium (IV) salt, respectively, is in the range of (1 to 0.1) to (1 to 0.7). 
     
     
       3. The method according to  claim 2 , wherein the soluble niobate (V) is an alkali metal orthoniobate. 
     
     
       4. The method according to  claim 3 , wherein the alkali metal orthoniobate is selected from the group consisting of Li 3 NbO 4 , Na 3 NbO 4 , K 3 NbO 4 , Rb 3 NbO 4 , and Cs 3 NbO 4 . 
     
     
       5. The method of  claim 4 , wherein the at least one zirconium (IV) salt is selected from the group consisting of zirconium (IV) oxychloride ZrOCl 2 , zirconium (IV) tetrachloride ZrCl 4 , zirconium (IV) oxysulfate ZrOSO 4 , and zirconium (IV) sulfate Zr(SO 4 ) 2 . 
     
     
       6. The method according to  claim 5 , wherein the step of converting the obtained granulated mixed hydrated niobium and zirconium oxide into a is carried out with concentration of the lithium-containing compound in the rage of 0.05 M to 0.2 M. 
     
     
       7. The method according to  claim 5 , wherein the step of calcining the Li-form of the granulated mixed hydrated niobium and zirconium oxide to obtain a granulated mixed lithium, niobium, and zirconium oxide, which comprises a tripled mixed oxide and is a Li-form of an inorganic ion-exchanger, is carried out at a temperature in the range of 450° C. to 600° C. 
     
     
       8. The method according to  claim 4 , wherein the step of freezing is carried out at a temperature in the range of −3° C. to −10° C. during time from 20 hours to 40 hours. 
     
     
       9. The method according to  claim 3 , wherein the at least one zirconium (IV) salt is selected from the group consisting of zirconium (IV) oxychloride ZrOCl 2 , zirconium (IV) tetrachloride ZrCl 4 , zirconium (IV) oxysulfate ZrOSO 4 , and zirconium (IV) sulfate Zr(SO 4 ) 2 . 
     
     
       10. The method according to  claim 9 , wherein the step of freezing is carried out at a temperature in the range of −3° C. to −10° C. during time from 20 hours to 40 hours. 
     
     
       11. The method according to  claim 2 , wherein the step of converting the obtained granulated mixed hydrated niobium and zirconium oxide into a is carried out with concentration of the lithium-containing compound in the rage of 0.05 M to 0.2 M. 
     
     
       12. The method according to  claim 2 , wherein the step of calcining the Li-form of the granulated mixed hydrated niobium and zirconium oxide to obtain a granulated mixed lithium, niobium, and zirconium oxide, which comprises a tripled mixed oxide and is a Li-form of an inorganic ion-exchanger, is carried out at a temperature in the range of 450° C. to 600° C. 
     
     
       13. The method according to  claim 1 , wherein the soluble niobate (V) is an alkali metal orthoniobate. 
     
     
       14. The method according to  claim 13 , wherein the alkali metal orthoniobate is selected from the group consisting of Li 3 NbO 4 , Na 3 NbO 4 , K 3 NbO 4 , Rb 3 NbO 4 , and Cs 3 NbO 4 . 
     
     
       15. The method according to  claim 1 , wherein the at least one zirconium (IV) salt is selected from the group consisting of zirconium (IV) oxychloride ZrOCl 2 , zirconium (IV) tetrachloride ZrCl 4 , zirconium (IV) oxysulfate ZrOSO 4 , and zirconium (IV) sulfate Zr(SO 4 ) 2 . 
     
     
       16. The method according to  claim 1 , wherein the step of freezing is carried out at a temperature in the range of −3° C. to −10° C. during time from 20 hours to 40 hours. 
     
     
       17. The method according to  claim 1 , wherein the step of converting the obtained granulated mixed hydrated niobium and zirconium oxide into a is carried out with concentration of the lithium-containing compound in the rage of 0.05 M to 0.2 M. 
     
     
       18. The method according to  claim 1 , wherein the step of calcining the Li-form of the granulated mixed hydrated niobium and zirconium oxide to obtain a granulated mixed lithium, niobium, and zirconium oxide, which comprises a tripled mixed oxide and is a Li-form of an inorganic ion-exchanger, is carried out at a temperature in the range of 450° C. to 600° C.